cfg80211: check iface combinations only when iface is running

commit f8cdddb8d61d16a156229f0910f7ecfc7a82c003 upstream.

Don't validate interface combinations on a stopped
interface. Otherwise we might end up being able to
create a new interface with a certain type, but
won't be able to change an existing interface
into that type.

This also skips some other functions when
interface is stopped and changing interface type.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[Fixes regression introduced by cherry pick of 463454b5dbd8]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/wireless/util.c b/net/wireless/util.c
index b5b6890..0eb6cc0 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -805,7 +805,7 @@
 	     ntype == NL80211_IFTYPE_P2P_CLIENT))
 		return -EBUSY;
 
-	if (ntype != otype) {
+	if (ntype != otype && netif_running(dev)) {
 		err = cfg80211_can_change_interface(rdev, dev->ieee80211_ptr,
 						    ntype);
 		if (err)